Analysis of the toroidal HVDC grounding systems in horizontal multilayer soils

A Fredholm integral equation of the first kind has been developed for analyzing the performance of the toroidal high-voltage direct current (HVDC) grounding system buried in the horizontal multilayer soil. The method of moment is used to solve the equations. The formulation of potential in the earth due to a circular current is proposed in closed form by means of conception of the complex resistivity and depth, which leads to the saving of the computational time greatly. The numerical results show the good agreements with those in other papers and the measured data. Index Terms--Galerkin's moment method, grounding electrodes, high-voltage direct current (HVDC), multilayer soil.